Modern communication systems utilize radio frequency (RF) filters to convert electrical energy into mechanical energy and vice versa. Some RF filters employ film bulk acoustic resonators (FBARs), sometimes called thin-film bulk acoustic resonators (TFBARs). With the growing number of frequency bands and modes of communications, the quantity of RF filters in a typical mobile device has significantly increased.
As will be appreciated, the figures are not necessarily drawn to scale or intended to limit the disclosure to the specific configurations shown. For instance, while some figures generally indicate straight lines, right angles, and smooth surfaces, an actual implementation of a structure may have less than perfect straight lines, right angles, and some features may have surface topology or otherwise be non-smooth, given real world limitations of the processing equipment and techniques used. In short, the figures are provided merely to show example structures.